Engine-Codes - Mercedes-benz - P0177 MERCEDES-BENZ

P0177 MERCEDES-BENZ - Fuel Composition Sensor Circuit Range/Performance

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What is this?
Table of contents

P0177 MERCEDES-BENZ Possible Causes

  • Flexible Fuel (FF) sensor to Vehicle Power (VPWR) circuit harness open or shorted
  • FF to VPWR circuit poor electrical connection
  • Open in FF sensor signal circuit
  • Short to ground in FF sensor signal circuit
  • Fuel contamination

How is the P0177 MERCEDES-BENZ code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

Tech Notes

Replaced Fuel Composition Sensor

What is the cost to diagnose the P0177 MERCEDES-BENZ code

Labor: 1.0

The cost to diagnose the P0177 MERCEDES-BENZ code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
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Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0177 MERCEDES-BENZ Meaning

Fuel Composition Sensors are used to determine the amount of ethanol alcohol in the gasoline. Normally, a gasoline engine should not have more than 10% ethanol alcohol in the fuel for proper operation. Some vehicles have a Flexible Fuel (FF) system on them that allow them to run on up to 85% ethanol alcohol in the fuel. The fuel composition sensor sends a frequency modulated signal to the engine controller which is proportional to the alcohol content of the fuel. The injector pulse width and the ignition timing are modified for the increased alcohol content. It takes almost twice the amount of alcohol compared to gasoline to produce the same power.

More Information

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